US1663513A - Ram drive for underfeed stokers - Google Patents

Description

March 20, 1928.

1,663,513 c. l.. HowsE RAMDRIVE FOR UNDERFEED STOKERS Filed March 2. 1922 March 20, 1928. f

V c. L. HowsE' RAM DRIVE FOR UNDERFEED STOKERS Filed Marcha, 1922 2 sheets-snee: 2

. v I j Patented 20, 1928. y

UNITED STATES PATENT OFFICE.

CURTIS I.. Howsn, or nnTRoIT,-IIICHIGAN, AssIGNoR, RY MRSNE ASSIGNMENTS, To"

RILEY sToxnR CORPORATION, or WORCESTER, MASSACHUSETTS, A ooRroRATIc-N OF MASSACHUSETTS.

RAM nam 'non UNnnRrEnn SToxnRs.

Application med Iarcn 2, 1922. serial Nc. $40,646.

tervals between operations of other rams ofthe group, but with the timing of operation of all rams generally harmonizedwith the .demand of the steam boiler, requisite for maintenance of proper steam pressure therein. Other'objects of my invention are to provide a ram drive installation madeup of units of relatively "simple construction, in coordinationand arrangement accommodating simplicity and convenience in the placement of piping, location of operating parts and flexibility of adaptation to widely varying detail requirements; and further objects of the invent1on will become apparent from the following description taken in conjunction with the accompanyinr drawings.

In the drawings I have il ustrated my invention in diagrammatic Iform only for ease of understanding, since proportions and details will be Widely varied accordin to the needs of the particular plant. In suc drawings, Fig. 1 is a diagrammatic perspective of a systemembodying my invention, having several sources of return-pressure .supply which may be used alternatively or supplementally one to the other; Fig. 2 is a skeletonized diagram of a valve Construction showin its operating parts spread out somewhat; Iig. 2 is a conventionalized detail of the valve showing itsrport-arrangement; Fig. 3 is a simplified diagram showing an accumulator onl as the returnressure suply-source, and ig. 4 is a simi ar simplified diagram showing an air-pressure return-actuation. y. The furnace 10 may have each of its un- `derfeed retorts, not shown, Supplied with fuel from a hopper 11 by means of a ramstructure 12 of known design, the plunger of which is reciprocable by a suitable enine 13. This may comprise a suitable cyllnder 14 closed at both ends and containing the piston 15 connected to the r'am plun er. Air may be supplied to the wlnd-cham r.

below the retorts by afan 16, the speed of vwhich may be varied automatically for increase of the air supply as boiler pressure drops, and decrease as the pressure rises. As one means for this purpose the fan 16 may be driven by an electric motor 17 the speed of which is controlled by a rheostat 18 which 1s governed by a pressure regulator 19 connected with the steam header 20 of a suitable boiler 21. It is desirable that the fuel also be fed at an increased rate as boiler-pressure drops, and to this end the feed-controlling appliances should be govy erned in accordance with boiler pressure, so that conveniently this regulation ma be effected from the fan shaft' as will hereafter be described. Alsov .it is desirable that this control be supplemented by control of the periodicity of operation of each ram 1nd1vidual1y,and this requirement, too, is ac'- commodated in my present system.

The rams are actuated on their feed stroke hydraulically, preferably against"a constant counter-pressure which, when the hydraulic feeding pressure is relieved, will return the piston on its idle stroke or out-stroke. In the specific construction shown, the liquid employed, such as oil, is drawn from a supply source or tank 23 by a pump 24 which may be of any suitable construction adapted to develop the y requisite pressure, and is forced to tank 32 from which it flows through a supply header '25 and respective branch pipes 25 to the valves 26, respective to the several engines (as indicated by solid, featherless arrows), which valves 26 will operate at appropriate'times to open communication between said pressure pipes and the pipes 27 which lead from the respective yalves, each' to the head end or outer-end of its engine cylinder. At another period in the operation of each valve it may connect sure tank between the pump'and the high 1 pressure header 25, and the pump is illustrated as connected by pipe 30, which includes a check-valve 31 for prevention of reverse iiow, with the ressure tank 32 which will contain a bod o compressed air in the space 33 above t e liquid 'body' 34. For peresent pur oses this pressure chamber may regarde as closed at its upper end, as 1t will be upon closure of the manual valve 35. Pipe 25 is directly connected with the tankr below the liquid 1evel. In some instances, also, it is desirable to insure very posltively against the development of too h1gh a pressure in the hydraullc system, and this may be done by connecting a suitable unloadmg valve or by-pass valve 36 between pipe and return pipe 28, and also by providing a pressure gauge 37 having switch contact included in the electric circuit 38 for a motor 39 utilized to drive the pump. It will be understood that the pump may be otherwise operatedv and yet conveniently subjected to pressure control.

Return pressure, substantially less than the feeding pressure, may be constantly supplied tothe inner or ram end of the respective `cylinders through branch pipes 40' of a low pressure header 40, and substantially constant low pressure may be sup lied to this header in various ways. If desired, the

pressure of high pressure pipe 25, reduced by suitable valve mechanism, may be applied to pipe 40, and to this end I have illustrated a conventional pressure reduction valve 41 connected by pipe 42 with high pressure header 25 and by pipe 43, containing-manual valves 42 and 44, with the low pressure header 40. The course of counter-pressure through these connections is indicated by featherless dotted arrows. To insure against development of too high a pressure in the header 40 a relief valve 45 may be connected by pipe 46 between said pipe 43 and the relief header 28.

Now it will be apparent that with pressure in header 40 maintained at say 40 pounds, .and the pressure in pipe 25 maintained at approximately 120 plounds, the opening of a valve 26 to establis communication between ipes 25 and 27 will cause the piston to be orcibly impelled on its instroke or feeding stroke, and as soon as valve 26 cuts o this connection and opens commun'ication between pipe 27 and relief pipe 28, the lower return pressure will force the piston back on its idle orA out-stroke, expelling the liquid from the Vhead end of the cylinder for return to the supply tank 23.

For the stated valve-operatlon, I preferably utilize a form of ratchet-advance valve that is generically known, each such valve having means for its step-length. struction shown in may, through its ports 51 and 52, estabhsh communication between pipe 27 and either In thi skeletonized conindividual adjustment of Fig. 2 the rotary valve 50 mesme of pipes 25' and 28'. This valve is rotated by shaft 53 on which is fixed a ratchet wheel 54. A rocking frame 55, coaxial with the shaft throws back and forth the loosely pivoted arm 56 of the actuating pawl 57 for the ratchet, step length being variable by lost-motion `adjustment between the two abutments 58 .and 59 vof said frame which work on opposite sidesv of the pawl-arm, the one abutment to retract it, the other to advance it. One of these abutments is provided on a sleeve 60 rotatable with respect to the frame and adapted to be fixed in adjusted position by a suitable latch 61 co-` acting with an indexing rack 61a on the main frame structure. order to insure, however, that the port 52 for the high pressure supply will always be brought into full register with-pipe 27 'by a single step motion of the rocking frame, and carried fully out of register on the next step motion, ratchet 54 has a stripped portion 54 and has xed to ita two-toothed supplemental ratchet 62 coacting with a pivoted pawl 63 non-adjustably carried by the frame 55. At one period of operation the pawl 57 acts on the last tooth of the main ratchet 54, and this brings the first tooth of the two-toothed ratchet 62 into position to be engaged by pawl 63. Such pawl imparts two full-stroke movements to the valve-shaft, with the result above stated.

Provision is preferably made for rocking the frame of each valve at a rate consistent with the speed of rotation of the fan shaft. To this end the valve frames are all connected together by links 65 to rock in unison, and one of them is operated by a link 66 from a crank member 67 whichis driven from the fan shaft, as through speed reducing belting and pulleys 68.

In the operation of the equipment thus far described, the pump 24 maintains liquid underA high pressure in the pressure tank 32, preferably employed, and in the supply line 25, and also maintains in the pipe 40 a lower liquid pressure, this return pressure being-supplied through the ressure reducing valve 41 when cut-off va ves 42 and 44 are open, the maximum pressure that may exist in the header 40 being determined by the relief valve 45 which is set consistently with and ve slightly above the pressuresetting of va ve 41. Valves 26 have their ratchet operating mechanisms constantly driven, as by connections from the fan shaft as a convenient source of power, and, with the construction shown in Fig. 2, each valve may be adjusted so that its ratchet mechanism will take either a long step or a short step according to the lost motion permitted between abutments 58 and 59. Thus, after a predetermined number of steps, the valve 1s rought to position to connect high pressure branch plpe 25 with the cylmder- 1pc 27, and the liquid under high pressure acting ,through the ressure-connections as movement, and under the substantialliy e drives the piston 15 of the appropriate ram engine 13 to in-stroke position as shownv in section in'Fig. 1. The liquid under lower pressure that normally iills the inner or ramend of the cylinder is forced out by way of pipes 40, 43 and 46, through the relief valve 45, to the return header 28, to iowv backinto the liquid supply chamber 23. Since the provision of two-toothed auxiliary ratchet. 62 in the valve operating mechanism insures that the stated valve connection between pipes 25 and 27 will always be fully openedv by a single step-movement of the valve frame 55, and in the next succeeding oscillation of the frame will fully close said connection but open connection between pipes 27 and 28', the ram is retracted immediately after its power stroke. The opening of this connection between the engine pipe 27 and the branch 28 of the return header 28 frees the p-iston 15 for its return constant-return-pressure supplied to hea r 40,

and its branch 40 to the engine,the piston 1 5' is driven on its out-stroke,expellin0r the liquid from'thehead end of the cylinder ,through said pipes 27 and 28 back to the.

supply chamber 23, (as shown by solid, half. feathered arrows, Fig. 1). Through suitable pressure responsive ;means, the rapidity of oscillation of the actuatingframes 55 of the several valves 26 may be increased as boiler pressure drops and decreased as boiler pressure rises, the specificconstruction illustratively shown providin for pressure regulation of the speed of t e fan, and consequently of the valve mechanism vdriven by the fan-shaft. 4

If absolute uniformity of return pressure in the header 40be desired, the provision heretofore described for liquid supply to said header from the pipe 25 through the reduclng valve 41 may be put out of service by closure of cut-oli valves 42 and 44 (or such provision eliminated) Vand the return pressure header 40 may be connected through plpe 71 (including a cut-off valve 71') with an accumulator 72 in which a liquid body is maintained under constant pressure in a cylinder by the action of piston 73 borne upon by a constant weight 74. Of course by closing off the valve 71 this auxiliaryy or supplemental source of pressure suppl may put out of service, instead of elivering counter-pressure in the course indicated by a` dotted, full-feathered arrow.

As a. further or alternative source of return-pressure supply a connection may be established between a properly-'maintained source of air ressure and the header 40, and in the speci c construction shown the air space 33 of supply tank 32 is shown as connectible throng4 the cut-oli' valve 35 and `sure setting. of valve through a suitable pressure-reducing valve 76, both of which are connected in a. pipe,

77, with an air chamber 78, the outlet pipe 79 of whichmay be opened through a manual cut-off valve 80 to the header 40 (as indicated by dotted half-feathered arrow, Fi

ber, as by means of an air pump 83, and this is especially useful where the air pressure from ,chamber 32 is utilized for .returningv the' ram-engine pistons. Thus, in the speciic constructionv -dia rammatically illustrated in Fi 1 a liqui -levelresponsive device in cham er 32;, such as the float 84, may suitably control the operation of pump 83 as 'by working the switch 85 controlling the circuit 86 for an electric motor 87 that drives the air pump. This switch may also control the circuit 38 for the motor of the liquid pump. Upon rise of the liquid body 34 to a predetermined level the liquid pump 24 ceases to operate and the air pump is thrown into operation, b virtue o 'the action of switch in opening the circuit for the motor 39 and closing the circuit for the motor 87. Of course by closing the manual cut-0E valves 35 a.nd.80 the air system for sup-- driving the ram engines on their powerstrokes, prov1s1on may be made or`steam actuation in emergency, as in the event of a break-down of the main liquid pump 24. Thus, as shown in Fig. 1, a steam supply pipe 90 tapped from steam header 20 or other suitable source of supply but normally closed by a cut-ofi valve 90, may be connected to the normally dead end of the high pressure pipe 25, a connection 92, controlled by a manual valve 92 that normally stands closed, may be made from the return pipe or header 28 to any suitable point of utilization of exhaust steam, and the manual cutoi valve 93 (normally open) may be provided between this connection 92 and the liquid sup ly chamber 23.

Fig. 3 s ows, in simpliied diagram, such of the parts illustrated in Fig. 1 (and identied by like numerals) as will incorporate the accumulator 72 as the sole source of counter-pressure; and Fig. 4 shows, in like manner, such parts of Fig. 1 as would make the air chamber 78 the sole source of counter-pressure.

las

It will be understood that by providing a rotary pump having a suitable maximum pressure capacity, which will not injure the system in any event, some of the protective provisions herein suggested may be eliminated, but a system as hereinbefore described may be'operated with any suitable form of pump, with adequate protection to all of the devices employed, and with insurance of very prompt forceful operation of the ram-engine for efficient results automatically attained. p

While I have herein set forth in some -detail particular embodiments of my invention, some details of which I may claim for their specific advantages, it will be understood that I do not limit my invention in itsbroader aspects to details of the specific mechanisms as set forth and that changes in construction and arrangement of parts ma be made without departure `from the spirit of my invention within the scope of the appended claims.

I claim:

1. In a driving system for s toker rams, they combination with a plurality of rams, of respective reciprocating engines therefor, means including a hydraulic pump and a storage tank to serve all of said rams for developing engine-operating high pressure, high pressure connections between said tank vand one end only of each said engine and including foreach said engine an automatic controlling valve, each said valve being operable to lconnect said end only of its engine withjthe high pressure and alternately l to relieve Ypressure therein, means for operating said valves, settable individually 'as to periodicity of operation of each said valve, and means independent of said valves for supplying lower pressure to the other end of each engine for effecting its return stroke whn the high pressure is relieved as aforesai 2. In a driving system for stoker rams, the combination with a plurality of rams, of respective reciprocatin engines therefor, means including a hy raulic pump and a :,eeasia storage tank to serve all of said ramsfor developing engine-operating high pressure, high pressure connections between said tank and one end only of each said engine and including for each saidengine an automatic controlling valve, each said valve being operable to connect said end only of its engine with the high pressure and alternately to relieve pressure therein, means for operating said valves, settable individually as to periodicity 4of operation of each said valve, and means independent of said valves for supplying lower, constant hydraulic pressure to the other end of eachl engine for effecting its return stroke when the high pressure is relieved as aforesaid.

3. The combination with a reciprocating ram-engine, of a source of hydraulic high pressure supply, a pressure tank connected therewith normally to contain a body of liquid and a body of air under pressure, a ram-engine controlling-valve and connections therefor, said valve'being automatically operable to connect one end of the ram-engine with the liquid supply area of the pressure tank and, alternately, with the suction side of the pump, pump driving means., means for supplying air under ressure to said supply tank, and liquidevel responsive means controlling the operation of said air supply means.

4. The combination with a reciprocating ram-engine, of a source of hydraulic high pressure supply, a pressure tank connected therewith normally to contain a body of liquid and a body of air under pressure, a

ram-engine controlling-valve and connections therefor, said valve being automat-ically operable to connect one end of the ramengine with the liquid supply area of the pressure tank and, alternately, with the suction side of the pump, pump-driving means, means for supplying air under pressure to said supply tank, and liquid-level responsive means controlling the operation of said` air supply means and -said engine-operating means.

CURTIS L. HOWSE.

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